Sound Signal Processing Device Frequency Band Extraction
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Solution Overview
Problem
Existing sound signal processing technologies face challenges in effectively extracting main sounds from mixed sounds, particularly in removing leakage and reverberant sounds without compromising sound quality or limiting audition positions.
Innovation Solution
A sound signal processing device that divides mixed sound signals into frequency bands, calculates level ratios between main and unnecessary sounds, and adjusts time differences to extract the main sound, allowing for accurate separation without pseudo-waveform deduction or phase cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If waveforms of pseudo reverberant sound are generated and deducted from mixed sound on the time axis, then reverberant sound can be removed, but sound quality becomes poor unless waveforms are accurately generated
Solution Approach 1:
The patent segments the sound signal into multiple frequency bands and processes each band separately. By dividing the reverberation removal task across frequency bands, the system can accurately generate pseudo reverberant waveforms for each band without compromising overall sound quality, resolving the contradiction between removing reverberation and maintaining sound quality
Solution Approach 2:
The patent changes the processing approach from time-axis deduction to frequency-domain analysis. By transforming the problem into the frequency domain and using level ratio calculations, the system can more accurately identify and remove reverberant components while preserving the quality of direct sound, thus resolving the quality degradation issue
2Object-generated harmful factors
If a phase-inverted wave of reverberant sound is generated and emanated from an auxiliary speaker, then reverberant sound can be cancelled, but audience positions where cancellation occurs are limited
Solution Approach 1:
The patent extracts reverberant sound components from the mixed sound signal through frequency band analysis and level ratio calculation. By separating the reverberation from the direct sound in the frequency domain and removing it digitally, the system eliminates the need for physical auxiliary speakers, thereby enabling reverberation cancellation for all audience positions without spatial limitations
Solution Approach 2:
The patent replaces the mechanical approach of using auxiliary speakers for phase cancellation with a digital signal processing approach. By using frequency domain analysis and level ratio-based separation, the system achieves reverberation removal through computational methods rather than physical acoustic cancellation, thus providing universal effectiveness across all listening positions
3Loss of information
If mixed sound is processed to remove leakage sound, then sound separation can be achieved, but sound quality deteriorates due to inaccurate waveform generation
Solution Approach 1:
The patent divides the sound signal into multiple frequency bands and processes each band independently. This segmentation allows for more precise identification of leakage sound components in each frequency range, enabling effective separation while maintaining the quality of the desired sound through frequency-specific processing
Solution Approach 2:
The patent transforms the leakage sound removal process from time-domain waveform manipulation to frequency-domain level ratio analysis. This parameter change enables more accurate identification and separation of leakage components without the quality degradation associated with time-axis waveform deduction
Data Source
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AI summary
A sound signal processing device that is capable of suitably extracting main sound from mixed sound in which unnecessary sound (for example, leakage sound and reverberant sound) is mixed with the main sound. More specifically, a mixed sound signal in the time domain including first sound and second sound, and a target sound signal in the time domain including sound corresponding to at least the second sound, which have temporal relation in their entirety or in part, are each divided into a plurality of frequency bands. A level ratio between the two signals is calculated at each frequency. Based on the level ratio, a signal of the first sound that is included in the mixed sound signal is extracted.